#region Utf8Json License https://github.com/neuecc/Utf8Json/blob/master/LICENSE
// MIT License
//
// Copyright (c) 2017 Yoshifumi Kawai
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

#endregion

using System;

namespace Nest.Utf8Json
{
	internal class ArrayPool<T>
	{
		private readonly int _bufferLength;
		private readonly object _gate;
		private int _index;
		private T[][] _buffers;

		public ArrayPool(int bufferLength)
		{
			_bufferLength = bufferLength;
			_buffers = new T[4][];
			_gate = new object();
		}

		public T[] Rent()
		{
			lock (_gate)
			{
				if (_index >= _buffers.Length)
					Array.Resize(ref _buffers, _buffers.Length * 2);

				if (_buffers[_index] == null)
					_buffers[_index] = new T[_bufferLength];

				var buffer = _buffers[_index];
				_buffers[_index] = null;
				_index++;

				return buffer;
			}
		}

		public void Return(T[] array)
		{
			if (array.Length != _bufferLength)
				throw new InvalidOperationException("return buffer is not from pool");

			lock (_gate)
			{
				if (_index != 0)
					_buffers[--_index] = array;
			}
		}
	}
}
